Air purification device

ABSTRACT

A purification device for disinfecting and filtering intake air is disclosed. The purification device comprises a housing provided with a number of inlet perforations for allowing the intake air to enter the housing and a number of air outlet perforations for allowing air purified by the purification device to leave the housing. The purification device moreover comprises a fan arranged inside the housing to suck the intake air into the housing and blow the purified air out of the housing. The purification device further comprises an ultraviolet radiation lamp arranged inside the housing to irradiate the intake air. The purification device also comprises a high-efficiency particulate air (HEPA) filter arranged to filter the intake air before the intake air leaves the housing as purified air. The filter comprises a plurality of pleats arranged in such a manner that the angle between adjacent pleats is 30 degrees or less.

FIELD OF INVENTION

The present invention relates to an air purification device. The presentinvention more particularly relates to a portable air purificationdevice.

BACKGROUND

Population growth compounded with rapid urbanization has amplified thepotential for bacteria and viruses to spread quickly. Accordingly, thereis an increasing need for purification and disinfection of air in orderto eliminate the risk of infecting vulnerable hospitalized people andnursing home residents. The Coronavirus Disease COVID-19 has brought therisk of infecting vulnerable older or hospitalized people as well asnursing home residents with various diseases into focus.

Thus, there is a need for an air purification device that can reduce therisk of infecting vulnerable people with viruses such as the Coronaviruscausing the Coronavirus Disease COVID-19.

Most viruses vary in diameter from 20 nm to 400 nm. Accordingly, eventhough many prior art air purification devices comprise an efficiencystandard of air filter such as a high-efficiency particulate air (HEPA)filter, these purification devices cannot effectively filter viruses dueto the small size of viruses. Accordingly, the prior art airpurification devices cannot be used to protect from airborne oraerosolized pathogens.

Filters meeting the HEPA standard must remove from the air that passesthrough the filter at least 99.95% (European Standard) or 99.97% (ASME,U.S. DOE), respectively, of particles whose diameter is equal to 0.3 μm.

It is an object of the present invention to provide an air purificationdevice that can efficiently purify virus containing air and thus reducethe risk of infecting vulnerable people with viruses that causeinfectious diseases.

SUMMARY

The object of the present invention can be achieved by purificationunits and methods disclosed herein.

A purification device according to the invention is a purificationdevice for disinfecting and filtering intake air, wherein thepurification device comprises:

-   -   a housing provided with a number of inlet perforations for        allowing the intake air to enter the housing and a number of air        outlet perforations for allowing air purified by the        purification device to leave the housing;    -   a fan arranged inside the housing to suck the intake air into        the housing and blow the purified air out of the housing;    -   an ultraviolet radiation lamp arranged inside the housing to        irradiate the intake air;    -   a high-efficiency particulate air (HEPA) filter surrounding the        ultraviolet radiation lamp and being arranged to filter the        intake air before the intake air leaves the housing as purified        air, wherein the filter comprises a plurality of pleats arranged        in such a manner that the angle between adjacent pleats is 30        degrees or less.

Due to the small acute angle θ, the retention capability of the filtercan be increased. Therefore, the purification device provides a moreefficient purification of virus containing air. Accordingly, by usingthe purification device to purify the air that vulnerable people areexposed to (e.g. in a hospital room or a room in a nursing home) it ispossible to reduce the risk of infecting vulnerable people with virusesthat cause infectious diseases.

In one embodiment, the angle between adjacent pleats is 28 degrees. Inone embodiment, the angle between adjacent pleats is 26 degrees. In oneembodiment, the angle between adjacent pleats is 24 degrees. In oneembodiment, the angle between adjacent pleats is 22 degrees. In oneembodiment, the angle between adjacent pleats is 20 degrees. In oneembodiment, the angle between adjacent pleats is 18 degrees. In oneembodiment, the angle between adjacent pleats is 16 degrees. In oneembodiment, the angle between adjacent pleats is 15 degrees. In oneembodiment, the angle between adjacent pleats is 14 degrees. In oneembodiment, the angle between adjacent pleats is 12 degrees. In oneembodiment, the angle between adjacent pleats is 10 degrees. In oneembodiment, the angle between adjacent pleats is 8 degrees or less.

The number of pleats is inversely related to the angle between adjacentpleats. Accordingly, it is possible to achieve a small angle betweenadjacent pleats by applying a large number of pleats.

Moreover, the total filter area is proportional to the number of pleats.Accordingly, it is possible to increase the total filter area byincreasing the number of pleats. It is an advantage to have a largefilter area because the filtering capacity (the maximum flow velocity)is proportional to the filter area.

The small angle between adjacent pleats makes it possible to make thevirus stick to inside surfaces of the HEPA filter. Since the filtersurrounds the ultraviolet radiation lamp, there is plenty of time toeliminate the virus by emitting ultraviolet radiation. Accordingly, thepurification unit has a unique ability to maintain virus particlesinside the space surrounded by the filter and irradiate the virusparticles with ultraviolet radiation that destroys the virus particles.

Since the filter does not allow any virus particles to pass through thefilter and since any virus particles present at the inside surface ofthe filter are killed by the ultraviolet radiation from the ultravioletradiation lamp, the filter contains no virus particles when the filterhas to be replace (during maintenance). Accordingly, it is not requiredfor service personnel to wear a hazmat suit or biohazard suit whenreplacing the filter. Moreover, service personnel can remove the filterwithout risking infection and the filter will not contain any virusparticles when the purification device is turned off. Accordingly, it issafe to move the purification device from one room to another.

In one embodiment, the distance from the UV lamp to the inside part ofthe HEPA filer is less than 20 cm.

In one embodiment, the distance from the UV lamp to the inside part ofthe HEPA filer is less than 18 cm.

In one embodiment, the distance from the UV lamp to the inside part ofthe HEPA filer is less than 16 cm.

In one embodiment, the distance from the UV lamp to the inside part ofthe HEPA filer is less than 14 cm.

In one embodiment, the housing is cylindrical.

In one embodiment, the housing is box-shaped.

In one embodiment, the HEPA filter area is 2 square meters or more. Inone embodiment, the HEPA filter area is 3 square meters or more. In oneembodiment, the HEPA filter area is 4 square meters or more.

In one embodiment, the lowest position of the UV lamp is the distalportion of the UV lamp, wherein an air gap is provided between thebottom plate of the housing and the distal portion of the UV lamp.

Hereby, shadow areas (non-irradiated intake air leaving the housing) canbe avoided. Moreover, particles that fall down to the bottom plate ofthe housing will be exposed to UV radiation from the UV lamp.Accordingly, particles on the bottom plate will be destroyed by the UVradiation.

In one embodiment, the light irradiation portion of the UV lamp extendsvertically.

In one embodiment, the housing comprises a bottom portion and a topportion configured to be detachably attached to the bottom portion.Hereby, access to the structures inside the housing is eased. This is anadvantage during maintenance and replacements.

In one embodiment, the fan is arranged in the top portion and the lightirradiation portion of the UV lamp is arranged in the bottom portion.Hereby, it is possible to introduce intake air into the top portion ofthe housing and blow the intake air into the bottom portion of thehousing and carry out a UV irradiation treatment of the air that isblown into the bottom portion of the housing.

In one embodiment, the inlet perforations are provided in the topportion, whereas the outlet perforations are provided in the bottomportion. Hereby, it is possible to guide the intake air into the topportion of the housing through the inlet perforations and blow thepurified air out of the bottom portion of the housing through outletperforations. Accordingly, the air flow pattern can be controlled in asimple and reliable manner.

In one embodiment, the fan has a horizontally orientated intake portionand a vertical output portion so that air pressurized by the fan leavesthe fan in a downwardly vertical direction. Since the intake air entersthe purification device in the top portion of the purification device,the intake air will not suck particles from floor level into thepurification device. The purified air will leave the purification devicein a lower level than the level at which intake air enters thepurification device.

Since the intake air enters the purification device in the top portionof the purification device, which is more than 200 mm above floor level,the purification device meets the requirements for being used inScandinavian hospitals, in which the floor zone and the zone extending200 mm above the floor is considered to be contaminated.

In one embodiment, the intake air enters the purification device in thetop portion of the purification device, which is more than 400 mm abovefloor level.

In one embodiment, the intake air enters the purification device in thetop portion of the purification device, which is in the range of 500-700mm above floor level.

In one embodiment, the height of the purification device is 60-100 cm.

In one embodiment, the height of the purification device is 70-90 cm.

In one embodiment, the height of the purification device is 75-85 cmsuch as 80 cm.

In one embodiment, the purification device is cylindrical and has adiameter in the range of 30-55 cm.

In one embodiment, the purification device is cylindrical and has adiameter in the range of 35-50 cm.

In one embodiment, the purification device is cylindrical and has adiameter in the range of 40-45 cm such as 42 cm.

In one embodiment, the fan is configured to deliver a flow up to 600m³/hour.

In one embodiment, the fan is configured to deliver a flow up to 560m³/hour.

In one embodiment, an additional layer is arranged at the outside of thefilter.

In one embodiment, the additional layer comprises activated carbon.

It may be advantageous that an additional layer is sandwiched betweenthe housing and the filter, wherein the additional layer comprisesactivated carbon. Hereby, the activated carbon can remove unwanted odorsby acting as an adsorbent which will trap the odor inside the activatedcarbon and retain it. Moreover, the additional layer can prevent UVlight from escaping to the surroundings.

In one embodiment, the top portion comprises a coarse filter slidablyarranged in one or more filter tracks extending axially near the rim ofthe top portion. Hereby, replacement of the coarse filter is eased.

In one embodiment, the top portion comprises two, three or fourseparated filter segments constituting a coarse filter, wherein thefilter segments are slidably arranged in filter tracks extending axiallynear the rim of the top portion.

In one embodiment, the top portion comprises four coarse filter segmentsthat are slidably arranged in filter tracks extending axially near therim of the top portion.

In one embodiment, the purification device comprises a particle sensorarranged to detect the level of particles in the air.

In one embodiment, the particle sensor is arranged inside the housing.Hereby, the particle sensor can detect the level of particles in theintake air entering the housing.

In one embodiment, the particle sensor is arranged inside the topportion of the housing. Hereby, the particle sensor can detect the levelof particles in the intake air entering the top portion of the housing.

In one embodiment, the particle sensor is arranged inside the bottomportion of the housing. Hereby, the particle sensor can detect the levelof particles in the intake air entering the bottom portion of thehousing.

In one embodiment, the purification device comprises a smoke alarm.Accordingly, the purification device can alert the people in the sameroom as the purification device in case of a fire.

In one embodiment, the smoke alarm is arranged inside the housing.Hereby, the smoke alarm can detect the level of smoke in the intake airentering the housing.

In one embodiment, the smoke alarm is arranged inside the top portion ofthe housing. Hereby, the smoke alarm can detect the level of smoke inthe intake air entering the top portion of the housing.

In one embodiment, the smoke alarm is arranged inside the bottom portionof the housing. Hereby, the smoke alarm can detect the level of smoke inthe intake air entering the bottom portion of the housing.

In one embodiment, the purification device comprises a control unitconfigured to control the speed of the fan depending on the detectedlevel of particles in the air.

In one embodiment, the control unit is configured to control the speedof the fan depending on measurements made by the smoke alarm.

In one embodiment, the control unit is configured to turn on the fan ifthe particle content of the intake air exceeds a predefined level.

In one embodiment, the control unit is configured to turn on the UV lampif the particle content of the intake air exceeds a predefined level.

In one embodiment, the control unit is configured to turn on the fan andthe UV lamp if the particle content of the intake air exceeds apredefined level.

In one embodiment, the control unit is configured to regulate the speedof the fan depending on the detected level of particle content (detectedby the particle sensor).

In one embodiment, the control unit is configured to adjust the speed ofthe fan to one of two or more predefined non-zero levels.

In one embodiment, the control unit is configured to adjust the speed ofthe fan to one of three or more predefined non-zero levels.

In one embodiment, the control unit is configured to adjust the speed ofthe fan in an ungraduated manner on the basis of the detected level ofparticle content. This may be done by fitting the fan with a permanentmagnet motor and a frequency converter. This will furthermore allow theprovision of the lowest possible energy consumption.

In one embodiment, the predefined particle content level is a defaultquantity. In another embodiment, however, the predefined particlecontent level can be adjusted by using a control unit of thepurification device.

A method according to the invention is a method for disinfecting andfiltering intake air, wherein the method comprises the following steps:

-   -   sucking intake air into a housing by means of a fan arranged        inside the housing, wherein the intake air enters the housing        through a number of inlet perforations provided in the housing;    -   blowing purified air by means of the fan out from the housing        through a number of air outlet perforations provided in the        housing;    -   irradiating the intake air by means of an ultraviolet radiation        lamp arranged inside the housing;    -   filtering the intake air by means of a HEPA filter before the        intake air leaves the housing as purified air, wherein the        method comprises the step of applying a filter that comprises a        plurality of pleats arranged in such a manner that the angle        between adjacent pleats is 30 degrees or less.

Accordingly, the method provides a way of purifying the air thatvulnerable people are exposed to (e.g. in a hospital room or a room in anursing home) in an improved manner. Accordingly, the method makes itpossible to reduce the risk of infecting vulnerable people with virusesthat cause infectious diseases.

In one embodiment, the angle between adjacent pleats is 28 degrees. Inone embodiment, the angle between adjacent pleats is 26 degrees. In oneembodiment, the angle between adjacent pleats is 24 degrees. In oneembodiment, the angle between adjacent pleats is 22 degrees. In oneembodiment, the angle between adjacent pleats is 20 degrees. In oneembodiment, the angle between adjacent pleats is 18 degrees. In oneembodiment, the angle between adjacent pleats is 16 degrees. In oneembodiment, the angle between adjacent pleats is 15 degrees. In oneembodiment, the angle between adjacent pleats is 14 degrees. In oneembodiment, the angle between adjacent pleats is 12 degrees. In oneembodiment, the angle between adjacent pleats is 10 degrees. In oneembodiment, the angle between adjacent pleats is 8 degrees or less.

The number of pleats is inversely related to the angle between adjacentpleats. Accordingly, it is possible to achieve a low angle betweenadjacent pleats by applying more pleats.

Moreover, since the total filter area is proportional to the number ofpleats, it is possible to increase the total filter area by increasingthe number of pleats.

In one embodiment, the irradiation is carried out by using a UV lamp,wherein the lowest position of the UV lamp is the distal portion of theUV lamp, wherein an air gap is provided between the bottom plate of thehousing and the distal portion of the UV lamp.

Accordingly, shadow areas (non-irradiated intake air leaving thehousing) can be avoided. Moreover, particles that fall down to thebottom plate of the housing will be exposed to UV radiation from the UVlamp.

In one embodiment, the light irradiation is carried out by using a UVlamp that extends vertically.

In one embodiment, the method applies a housing that comprises a bottomportion and a top portion configured to be detachably attached to thebottom portion.

In one embodiment, the method comprises the step of applying a fan thatis arranged in the top portion, wherein the light irradiation portion ofthe UV lamp is arranged in the bottom portion.

In one embodiment, the method is carried out by using inlet perforationsthat are provided in the top portion of the housing and outletperforations that are provided in the bottom portion of the housing.

In one embodiment, the method comprises the step of applying a fan thathas a horizontally orientated intake portion and a vertical outputportion so that air pressurized by the fan leaves the fan in adownwardly vertical direction.

In one embodiment, the method comprises the step of applying anadditional layer arranged at the outside of the filter.

In one embodiment, the method comprises the step of applying anadditional layer that comprises activated carbon.

In one embodiment, the method comprises the step of applying anadditional layer that is sandwiched between the housing and the filter,wherein the additional layer comprises activated carbon.

Hereby, the activated carbon can remove unwanted odors by acting as anadsorbent which will trap the odor inside the activated carbon andretain it. Moreover, the additional layer can prevent UV light fromescaping to the surroundings.

In one embodiment, the method comprises the step of applying a coarsefilter to filter the intake air before the intake air is sucked into thefan.

In one embodiment, the method comprises the step of applying a particlesensor arranged to detect the level of particles in the air.

In one embodiment, the method comprises the step of applying a particlesensor arranged inside the housing. Hereby, the particle sensor candetect the level of particles in the intake air entering the housing.

In one embodiment, the method comprises the step of applying a particlesensor arranged inside the top portion of the housing. Hereby, theparticle sensor can detect the level of particles in the intake airentering the top portion of the housing.

In one embodiment, the method comprises the step of applying a particlesensor arranged inside the bottom portion of the housing. Hereby, theparticle sensor can detect the level of particles in the intake airentering the bottom portion of the housing.

The method comprises the step of applying a smoke alarm to detect thesmoke content in the air.

The method comprises the step of applying a smoke alarm that is arrangedinside the housing. Hereby, the smoke alarm can detect the level ofsmoke in the intake air entering the housing.

In one embodiment, the smoke alarm is arranged inside the top portion ofthe housing. Hereby, the smoke alarm can detect the level of smoke inthe intake air entering the top portion of the housing.

The method comprises the step of applying a smoke alarm arranged insidethe bottom portion of the housing. Hereby, the smoke alarm can detectthe level of smoke in the intake air entering the bottom portion of thehousing.

In one embodiment, the method comprises the step of controlling thespeed of the fan depending on the detected level of particles in theair.

In one embodiment, the method comprises the step of applying a controlunit that is configured to control the speed of the fan depending onmeasurements made by the smoke alarm.

In one embodiment, the method comprises the step of applying a controlunit that is configured to turn on the fan if the particle content ofthe intake air exceeds a predefined level.

In one embodiment, the method comprises the step of applying a controlunit that is configured to turn on the UV lamp if the particle contentof the intake air exceeds a predefined level.

In one embodiment, the method comprises the step of applying a controlunit that is configured to turn on the fan and the UV lamp if theparticle content of the intake air exceeds a predefined level.

In one embodiment, the method comprises the step of applying a controlunit that is configured to regulate the speed of the fan depending onthe detected level of particle content (detected by the particlesensor).

In one embodiment, the control unit is configured to adjust the speed ofthe fan to one of two or more predefined non-zero levels.

In one embodiment, the method comprises the step of applying a controlunit that is configured to adjust the speed of the fan to one of threeor more predefined non-zero levels.

In one embodiment, the method comprises the step of applying a controlunit that is configured to adjust the speed of the fan in an ungraduatedmanner on the basis of the detected level of particle content. This maybe done by fitting the fan with a permanent magnet motor and a frequencyconverter. This will furthermore allow the provision of the lowestpossible energy consumption.

In one embodiment, the predefined particle content level is a defaultquantity. In another embodiment, however, the predefined particlecontent level can be adjusted by using a control unit of thepurification device.

DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription given below. The accompanying drawings are given by way ofillustration only, and thus, they are not limitative of the presentinvention. In the accompanying drawings:

FIG. 1 shows a perspective side view of an air purification deviceaccording to the invention;

FIG. 2 shows a perspective top view of the purification device shown inFIG. 1 ;

FIG. 3A shows a schematic top view of a filter according to theinvention;

FIG. 3B shows a close-up view of the filter shown in FIG. 3A;

FIG. 3C shows a prior art filter;

FIG. 4 shows a blown up (close-up) cross-sectional view of a portion ofthe inner space surrounded by a filter of a purification deviceaccording to the invention;

FIG. 5 shows a cross-sectional view of the bottom portion of apurification device according to the invention; and

FIG. 6 shows a flow chart illustrating how the purification deviceaccording to the invention can be autonomously controlled by means of aparticle sensor.

DETAILED DESCRIPTION

Referring now in detail to the drawings for the purpose of illustratingpreferred embodiments of the present invention, an air purificationdevice 2 of the present invention is illustrated in FIG. 1 .

FIG. 1 is a perspective side view of an air purification device 2according to the invention. The air purification device 2 comprises ahousing 10 having a bottom portion 16 and a top portion 18 configured tobe detachably attached to the bottom portion 16.

The bottom portion 16 is equipped with wheels 24 for improving themobility of the air purification device 2.

The top portion 18 is cylindrical and comprises a panel 28 provided onthe top of the top portion 18. In one embodiment, both the top portion18 and the bottom portion 16 comprise a display and one or more buttons.

The top portion 18 comprises a coarse filter 26 separated into fourfilter segments that are slidably arranged in filter tracks extendingaxially near the rim of the top portion 18. A plurality of air inletperforations 8 are provided in the cylindrical outer surface of the topportion 18. The coarse filter 26 is adapted to prevent objects largerthan a predefined size (e.g. 5 or 20 μm) to enter the inner space of thetop portion 18.

An electrically driven fan 12 is arranged inside the inner space of thetop portion 18. The fan 12 is an axial fan designed to cause intake air4 to flow through the fan 12 in an axial direction, parallel to theshaft about which the blades of the fan 12 rotate. The fan 12 has ahorizontally orientated intake portion and a vertical output portion sothat air pressurized by the fan 12 leaves the fan 12 in a downwardlyvertical direction.

The bottom portion 16 comprises an inner space 22 defined by anenclosing cylindrical high-efficiency particulate air (HEPA) filter. Anultraviolet radiation lamp 14 is centrally arranged in the inner space22. In a preferred embodiment, the ultraviolet radiation lamp 14 is agermicidal lamp (an ultraviolet C lamp). This may be an advantage sinceultraviolet C light (wherein the wavelength is in the range of 100 to280 nm) is capable of destroying and thus inactivating bacteria,viruses, and protozoa.

The UV C lamp 14 is arranged to irradiate the intake air 4 flowing intothe inner space 22 of the bottom portion 16. Accordingly, the UV C lamp14 is capable of disinfecting the intake air 4 flowing into the innerspace 22 of the bottom portion 16.

The purification device is configured to receive intake air 4 throughair inlet perforations 8 and allow the intake air 4 to flow through thefilter 20 and leave the bottom portion 16 through air outletperforations 8′ provided in the housing 10. In the top portion 18, fourcoarse filter segments 26 are slidably arranged in filter tracksextending axially near the rim of the top portion.

FIG. 2 illustrates a perspective top view of the purification device 2shown in FIG. 1 . It can be seen that the purification device 2comprises an electrical plug 30 for electrically connecting thepurification device 2 to the main. Hereby, the fan inside the housing 10of the purification device 2 can be powered. It can be seen that the topportion is provided with a plurality of air inlet perforations 8. Thebottom portion is provided with a plurality of air outlet perforations8′.

FIG. 3A illustrates a schematic top view of a filter 20 according to theinvention. The filter 20 comprises a plurality of pleats.

FIG. 3B illustrates a close-up view of the filter 20 shown in FIG. 3A,and FIG. 3C illustrates a prior art filter 20′. It can be seen that theangle α between the air flow direction 42 and the side portion of theadjacent pleat 32 of the filter 20 shown in FIG. 3B is smaller than theangle β between the air flow direction 42 and the side portion of theadjacent pleat 32 of the prior art filter 20′ shown in FIG. 3C.Moreover, it can be seen that the angle θ between adjacent pleats 32 ofthe filter 20 in the purification device 2 according to the invention issmaller than the angle ω between adjacent pleats 32 of the prior artfilter 20′ shown in FIG. 3C.

Due to the small acute angle θ, the retention capability of the filter20 is increased by having an increased number of pleats 32 compared tothe prior art filter shown in FIG. 3C.

In one embodiment, the angle θ is 30 degrees or less. In one embodiment,the angle θ is 28 degrees or less. In one embodiment, the angle θ is 26degrees or less. In one embodiment, the angle θ is 24 degrees or less.In one embodiment, the angle θ is 22 degrees or less. In one embodiment,the angle θ is 20 degrees or less. In one embodiment, the angle θ is 18degrees or less. In one embodiment, the angle θ is 16 degrees or less.In one embodiment, the angle θ is 14 degrees or less. In one embodiment,the angle θ is 12 degrees or less. In one embodiment, the angle θ is 10degrees or less. In one embodiment, the angle θ is 8 degrees or less.The number of pleats 32 is inversely related to the angle θ.Accordingly, it is possible to achieve a low angle θ by applying morepleats 32.

Moreover, the total filter area is proportional to the number of pleats32. Accordingly, it is possible to increase the total filter area byincreasing the number of pleats 32.

FIG. 4 illustrates a blown-up cross-sectional view of a portion of theinner space surrounded by a filter 20 of a purification device accordingto the invention. It can be seen that the filter 20 comprises athrough-going opening 38 configured to retain large sized virusparticles inside the inner space and allow small sized particle to passthrough the filter 20 through the through-going opening 38.

A large number of virus particles 36 are placed near the entry to thethrough-going opening 38. The virus particles 36 are interconnected andarranged in a cloud-formed formation 34 comprising virus particles 36and airway mucus. Accordingly, the cloud-formed formation 34 cannotescape through the through-going opening 38 even though the size of theindividual virus particles 36 is smaller than the width D of thethrough-going opening 38. In fact, the cloud-formed formation 34comprising virus particles 36 and airway mucus will stick to the insidesurface of the filter 20.

The virus particles 36 are irradiated with UV light from a UV lamp (e.g.a UV C lamp) arranged to irradiate the air and particles present in theinner space. Since the virus particles 36 are trapped inside the spacedefined by the inner surface of the filter 20, there is sufficient timeavailable to destroy the virus particles 36 by the ultraviolet (UV)light 50.

FIG. 5 illustrates a cross-sectional view of the bottom portion of apurification device 2 according to the invention. The purificationdevice 2 comprises a housing 10 provided with a plurality of air outletperforations 8′ for allowing purified air 6 to leave the purificationdevice 2.

The purification device 2 is configured to blow intake air 4 downwardsinto the inner space of the bottom portion of the purification device 2.Since the intake air 4 enters the purification device 2 in the topportion of the purification device 2, the intake air 4 will typicallynot suck particles from floor level into the purification device 2. Thepurified air 6 leaves the purification device 2 in a lower level thanthe level at which intake air 4 enters the purification device 2.

The purification device 2 comprises a UV light source (e.g. a UV C lamp)14 configured to irradiate the intake air 4 flowing into the inner space22 of the bottom portion of the purification device 2. Hereby, it ispossible to disinfect the intake air inside the inner space 22 of thebottom portion of the purification device 2.

The purification device 2 comprises a HEPA filter 20 having a largenumber of pleats (as explained with reference to FIG. 3B) in order toachieve a small angle α (e.g. of 15 degrees or less as shown in andexplained with reference to FIG. 3B) and a large total filter area.

The lowest position of the UV lamp 14 is the distal portion of the UVlamp 14 which is provided at a distance above the bottom plate 46 of thehousing 10. Accordingly, an air gap 44 is provided between the bottomplate 46 of the housing 10 and the distal portion of the UV lamp 14.Wheels are rotatably attached to the bottom plate 46.

An additional layer 40 may optionally be arranged at the outside of thefilter 20. In one embodiment, the additional layer 40 may be a layerthat comprises activated carbon. Activated carbon can remove unwantedodors by acting as an adsorbent which will trap the odor inside theactivated carbon and retain it.

An additional layer 40 may furthermore prevent UV light 50 from escapingto the surroundings.

In an embodiment, the additional layer 40 is an additional layer 40sandwiched between the housing 10 and the filter 20, wherein theadditional layer 40 comprises activated carbon.

FIG. 6 is a flow chart illustrating how the purification deviceaccording to the invention can be autonomously controlled by means of aparticle sensor.

Initially the purification device is turned on. In one embodiment, theparticle sensor of the purification device is turned on as default. Inone embodiment, the particle sensor of the purification device is turnedon and cannot be turned off.

The particle sensor of the purification device is configured to measurethe particle content of the intake air. If the particle content of theintake air exceeds a predefined level, the fan of the purificationdevice is turned on (or kept turned on if the fan has already beenturned on).

If, on the other hand, the particle content of the intake air does notexceed the predefined level, the fan of the purification device isturned off (or kept turned off if the fan has already been turned off).

In one embodiment, both the fan and the UV lamp are turned on if theparticle content of the intake air exceeds a predefined level.

In one embodiment, the speed of the fan is selected depending on thedetected level of particle content.

In one embodiment, the speed of the fan can be set to two or morepredefined non-zero levels.

In one embodiment, the speed of the fan can be set to three or morepredefined non-zero levels.

In one embodiment, the speed of the fan can be gradually ornon-gradually adjusted on the basis of the detected level of particlecontent. This may be done by fitting the fan with a permanent magnetmotor and a frequency converter. This will furthermore allow theprovision of the lowest possible energy consumption.

In one embodiment, the predefined particle content level is a defaultquantity. In another embodiment, however, the predefined particlecontent level can be adjusted by using a control unit of thepurification device.

LIST OF REFERENCE NUMERALS

-   2 Purification device-   4 Intake air-   6 Purified air-   8 Air inlet perforation-   8′ Air outlet perforation-   10 Housing-   12 Fan-   14 Ultraviolet radiation lamp-   16 Bottom portion-   18 Top portion-   20 Filter-   22 Inner space (enclosure)-   24 Wheel-   26 Coarse filters-   28 Control panel-   30 Electrical plug-   32 Pleat-   34 Cloud-formed formation-   36 Virus particle-   38 Through-going opening-   40 Additional layer-   42 Air flow direction-   44 Air gap-   46 Bottom plate-   50 Ultraviolet (UV) light-   α, β, θ, ω Angle-   D Width

The invention claimed is:
 1. A purification device for disinfecting andfiltering intake air, the purification device comprising: a housingprovided with a number of inlet perforations for allowing the intake airto enter the housing and a number of air outlet perforations forallowing air purified by the purification device to leave the housing; afan arranged inside the housing to suck the intake air into the housingand blow the purified air out of the housing; an ultraviolet radiationlamp arranged inside the housing to irradiate the intake air; and ahigh-efficiency particulate air (HEPA) filter surrounding theultraviolet radiation lamp and arranged to filter the intake air beforethe intake air leaves the housing as purified air, wherein the filter isdownstream of the fan relative to a direction of air flow through thepurification device, and wherein the filter comprises a plurality ofpleats arranged in such a manner that the angle between adjacent pleatsis 30 degrees or less.
 2. The purification device according to claim 1,wherein an air gap is provided between a bottom plate of the housing anda distal portion of the UV lamp.
 3. The purification device according toclaim 1, wherein the housing comprises a bottom portion and a topportion configured to be detachably attached to the bottom portion. 4.The purification device according to claim 3, wherein the fan isarranged in the top portion and a light irradiation portion of the UVlamp is arranged in the bottom portion.
 5. The purification deviceaccording to claim 3, wherein the inlet perforations are provided in thetop portion, whereas the outlet perforations are provided in the bottomportion.
 6. The purification device according to claim 3, wherein thefan is positioned within the top portion, has a rotational axis orientedhorizontal to a bottom plate of the housing, and has an outlet orientedperpendicular to the rotational axis.
 7. The purification deviceaccording to claim 1, wherein the fan has a horizontally orientatedintake portion and a vertical output portion so that air pressurised bythe fan leaves the fan in a downwardly vertical direction.
 8. Thepurification device according claim 1, wherein an additional layer issandwiched between the housing and the filter, wherein the additionallayer comprises activated carbon.
 9. The purification device accordingto claim 3, wherein the top portion comprises a coarse filter slidablyarranged in one or more filter tracks extending axially near a rim ofthe top portion.
 10. The purification device according to claim 1,wherein the purification device comprises a particle sensor arranged todetect the level of particles in the air.
 11. The purification deviceaccording to claim 1, wherein the purification device comprises a smokealarm.
 12. The purification device according to claim 10, wherein thepurification device comprises a control unit configured to control thespeed of the fan in dependence of the detected level of particles in theair.
 13. A method for disinfecting and filtering intake air, wherein themethod comprises the following steps: sucking intake air into a housingusing a fan arranged inside the housing, wherein the intake air entersthe housing through a number of inlet perforations provided in thehousing; using the fan to blow purified air out from the housing througha number of air outlet perforations provided in the housing; irradiatingthe intake air using an ultraviolet radiation lamp arranged inside thehousing; and filtering the intake air using a HEPA filter surroundingthe ultraviolet radiation lamp before the intake air leaves the housingas purified air, wherein the filter is downstream of the fan relative toa direction of air flow through the purification device, and wherein thefilter comprises a plurality of pleats arranged in such a manner thatthe angle between adjacent pleats is 30 degrees or less.
 14. The methodaccording to claim 13, wherein the irradiation is carried out by a UVlamp and an air gap is provided between a bottom plate of the housingand a distal portion of the UV lamp.
 15. The method according to claim13, wherein the housing comprises a bottom portion and a top portionconfigured to be detachably attached to the bottom portion.
 16. Themethod according to claim 15, wherein the fan is arranged in the topportion and a light irradiation portion of the UV lamp is arranged inthe bottom portion.
 17. The method according to claim 16, wherein theinlet perforations are provided in the top portion, whereas the outletperforations are provided in the bottom portion.
 18. The methodaccording to claim 13, wherein the fan has a horizontally orientatedintake portion and a vertical output portion so that air pressurised bythe fan leaves the fan in a downwardly vertical direction.
 19. Themethod according to claim 13, wherein an additional layer is sandwichedbetween the housing and the filter, wherein the additional layercomprises activated carbon.
 20. The method according to claim 13,further comprising a step of applying a coarse filter to filter theintake air before the intake air is sucked into the fan.
 21. The methodaccording to claim 13, further comprising a step of applying a particlesensor arranged to detect the level of particles in the air.
 22. Themethod according to claim 13, further comprising a step of applying asmoke alarm to detect the smoke content in the air.
 23. The methodaccording to claim 21, further comprising a step of controlling thespeed of the fan in dependence of the detected level of particles in theair.
 24. The method according to claim 16, wherein the fan is positionedwithin the top portion, has a rotational axis oriented horizontal to abottom plate of the housing, and has an outlet oriented perpendicular tothe rotational axis.